balance

Everyone remembers popping their first wheelie on a bike. It’s an exhilarating moment when you figure out just the right mechanics to get balanced over the rear axle for a few glorious seconds of being the coolest kid on the block. Then gravity takes over, and you either learn how to dismount the bike over the rear wheel, or more likely end up looking at the sky wondering how you got on the ground.

Had only this wheelie cheating device been available way back when, many of us could have avoided that ignominious fate. [Tom Stanton]’s quest for the perfect wheelie led him to the design, which is actually pretty simple. The basic idea is to apply the brakes automatically when the bike reaches the critical angle beyond which one dares not go. The brakes slow the bike, the front wheel comes down, and the brakes release to allow you to continue pumping along with the wheelie. The angle is read by an accelerometer hooked to an Arduino, and the rear brake lever is pulled by a hobby servo. We honestly thought the servo would have nowhere near the torque needed, but in fact it did a fine job. As with most of [Tom]’s build his design process had a lot of fits and starts, but that’s all part of the learning. Was it worth it? We’ll let [Tom] discuss that in the video, but suffice it to say that he never hit the pavement in his field testing, although he appeared to be wheelie-proficient going into the project.

For most of us, hacking is a hobby, something to pass a few idle hours and satisfy our need to create. Precious few of us get to live the dream of being paid to tinker; most of us need some kind of day job to pay the bills and support our hacking habits. This necessarily creates an essential conflict, rooted in the fact that we all only have 24 hours to spread around every day: I need to spend my time working so I can afford to hack, but the time I spend working to earn money eats away at my hacking time. That’s some catch, that Catch-22.

From that primary conflict emerges another one. Hacking is a hugely creative process, and while the artist or the author might not see it that way, it’s true nonetheless. Unless we’re straight-up copying someone else’s work, either because they’ve already solved the same problem we’re working on and we just need to get it done, or perhaps we’re just learning a new skill and want to stick to the script, chances are pretty good that we’re hitting the creative juices hard when we build something new. And that requires something perhaps even more limiting than time: inspiration. How you manage inspiration in large part dictates how productive you are in your creative pursuits.

Self-described “Inventor Dad” [pepelepoisson]’s project is called Stecchino (English translation link here) and it’s an Arduino-based physical balancing game that aims to be intuitive to use and play for all ages. Using the Stecchino (‘toothpick’ in Italian) consists of balancing the device on your hand and trying to keep it upright for as long as possible. The LED strip fills up as time passes, and it keeps records of high scores. It was specifically designed to be instantly understood and simple to use by people of all ages, and we think it has succeeded in this brilliantly.

To sense orientation and movement, Stecchino uses an MPU-6050 gyro and accelerometer board. An RGB LED strip gives feedback, and it includes a small li-po cell and charger board for easy recharging via USB. The enclosure is made from a few layers of laser-cut and laser-engraved material that also holds the components in place. The WS2828B WS2812B LED strip used is technically a 5 V unit, but [pepelepoisson] found that feeding them direct from the 3.7 V cell works just fine; it’s not until the cell drops to about three volts that things start to glitch out. All source code and design files are on GitHub.

Rehabilitating brain injuries where a patient’s sense of balance has been compromised is no easy task. Current solutions only trigger when the patient reaches a threshold and by then, it may already be too late for a graceful recovery. [Simon Merrett]’s SoleSense is being designed to give continuous feedback like a stock humans innate sense of balance. Therapists hope this will aid recovery by more closely imitating what most of us grew up with.

SoleSense relies on capacitive sensors arranged under the feet to know where the patients are placing their weight. [OSHPark] is providing the first round of flexible PCBs so some lucky sole is going to get purple inserts.

Outside of recovery, devices like this can teach better posture or possibly enhance a fully functioning sense of balance. That could improve physical performance. Who knows, we are finding new ways of perceiving the world all the time.

If you have a good sense of balance, you can ride a unicycle or get on TV doing tricks with ladders. We don’t know if [Hanna Yatco] has a good sense of balance or not, but we do know her Arduino does. Her build uses the ubiquitous HC-SR04 SONAR sensor and a servo.

This is a great use for a servo since a standard servo motor without modifications only moves through part of a circle, and that’s all that’s needed for this project. A PID algorithm measures the distance to the ball and raises or lowers a beam to try to get the ball to the center.

Balance: we humans take it for granted. Without the sense of balance provided by our inner ears, we would have a hard time standing or walking around. What’s easy for us can be very hard for machines though. Projects that balance things have long been a challenge for engineers, makers and hackers. And rightly so, as building a machine to keep an object in balance often requires some novel electronic and mechanical solutions. This week’s Hacklet is all about projects that keep an object – or themselves – in balance.

We start with [Manuel Kasten] and Balance Wheel. Inspired by a project at Chaos Communication Congress, [Manuel] created a hack that looks timeless. A stainless steel ball is balanced on top of a wooden wheel. The system detects the ball’s position using a solar cell. More light on the cell means the ball is slipping off the wheel. The system counteracts this by spinning the wheel to oppose the falling ball. In the old days this would have been an analog system. [Manuel] made things a bit more modern by using an ATmega644p processor. The video shows the wheel spinning a bit fast, as the system was tuned for a ping pong ball rather than a heavy steel roller.

Next up is [Jason Dorie] with Sideway. Sideway is a two-wheeled skateboard that self-balances. One of the best parts of this project is that most of the mechanical components are from electric scooters, which means they are easy to source. The frame is even easier: A solid piece of plywood supports the rider and all the electronics. Two scooter motors are driven by a Sabertooth 2x32A motor controller. A Parallax Propeller performs the balancing act, obtaining IMU data from an ITG3200 digital gyro and an ADXL345 accelerometer. Speed is controlled by leaning forward and back, like a Segway. Steering is controlled by a Wiimote nunchuck. Sideway is powered by 3 cell LiPo batteries. [Jason] says this ride gets a lot of attention every time he takes it out.

[Dominic Robillard] developed his Stair-climbing self-balancing robot as part of his masters degree at the University of Ottawa. We don’t know what grade his advisors gave him, but we give this project an A+. The robot is a 4WD off-road monster. Two heavy-duty drive motors give it tank style steering. The most impressive part of the robot are the two arms which allow it to roll its entire chassis up and over obstacles which would stop much larger robots. [Dominic’s] robot isn’t just statically balanced though – it can rear up and ride on two wheels Segway style. If it does tip over, the arms will lift it right back up!

Finally, we have [Paul Bristow] with Terabalance. [Paul] got his hands on an early copy of the TeraRanger One, a Time of Flight (ToF) sensor developed at CERN. He decided to test it out by using it to balance a ping pong ball on a wooden bar. The sensor had to be slowed down quite a bit in this application, data is only read about 1000 times a second and averaged. An Arduino reads the distance data from the sensor and uses that data to drive a hobby servo. No PID loops here, in fact, Terabalance is a great example of how a proportional only system will hunt forever. That said, it is good enough to keep the ball on the balance bar.

[Jim] loves gyros – not those newfangled MEMS devices, but old-fashioned mechanical gyroscopes. His obsession has pushed him to build this gyro stabilized two wheeler. We love watching hacks come together from simple basic materials and hand tools, with liberal amounts of hot glue to hold everything in place. That seems to be [Jim’s] philosophy as well.

This is actually the fifth incarnation of [Jim’s] design. Along the way he’s learned a few important secrets about mechanical gyro design, such as balancing the motor and gyro assembly to be just a bit top-heavy. [Jim’s] gyro is a stack of CDs directly mounted to the shaft of a brushed speed400 R/C airplane motor. The motor spins the CDs up at breakneck speed – literally. [Jim] mentions that they’ve exploded during some of his early experiments.

The gyroscope is free to move in the fore-aft direction. Side to side balance tilting is on the wheels themselves. The wheels are model airplane wheels, which have a curved tread. No cheating by using flat LEGO wheels in [Jim’s] lab! A potentiometer measures the tilt angle of the gyro. The voltage from the pot is fed into an Arduino Uno which closes the loop by moving a servo mounted counterweight.

The vehicle is controlled with a regular R/C plane radio. A servo steers the front wheel while another DC motor drives the rear wheel. Not only is [Jim’s] creation able to balance on its own, it can even make a U-Turn within a hallway.